This invention relates to switching circuits which employ a thyristor as the main switching element.
In the past, when two or more electrical loads were to be operated from a common source of electrical power it was necessary to provide a separate control wire for each load when the loads were to be energized individually, since a common switching point between the source and the loads would be useful only for energizing all of the loads at the same time. Many applications exist, however, for a method of individually controlling multiple loads that share a common power source from a common switching point. For example, it would be very convenient to be able to individually control a ceiling fan and an attached light fixture from a single wall switch in a room.
Accordingly, a primary object of this invention is to provide a method of energizing individual loads, or groups of loads, when the loads are connected to a common power supply, without having to provide a separate control line to each load.
Another object of the invention is to perform all switching functions without modifications to existing wiring, switches, loads or sources.
Still another object of the invention is to avoid the use of mechanical or electromechanical devices, such as relays, in the design.
A further object is to perform the necessary functions without digital logic circuits and attendant power supplies, thereby keeping the invention simple and inexpensive.
Other objects and advantages of the present invention will be obvious from the detailed descriptions and drawings presented herein.